Electrical regulator



March 27, 1951 c, 5, TOWNSEND 2,546,481

ELECTRICAL REGULATOR Filed Oct. 8, 1946 NVENTOR- I -ATTOR NEY- PatentedMar. 27, 1951 ELECTRICAL REGULATOR Carroll S. Townsend Fair Haven, N.J., assignor to Bendix Aviation Corporation, Teterboro, N. J acorporation of Delaware Application October s, 1946, Serial No. 701,939

3 Claims.

v The present invention relates to electrical regulators for alternatorsand more particularly to novel means for preventing the field of anexciter from reversing polarity upon a short occurring in the output ofthe alternator.

An cbjectof the invention is to provide a novel voltage regulator for analternator including switch means for restoring the exciter field toproper polarity upon reversal of the field.

Another object of the invention is to provide a novel 'Iirrill typeregulator including a regulating switch arm and contact and a thirdcontact engageable by the switch arm upon reversal of the polarity ofthe exciter field for restoring the exciter field to proper polarity bythe switch arm closing the third contact and thereby a circuit whichapplies a proper polarity to the exciter field so that the regulator mayonce again work properly.

These and other objects and features of the invention are pointed out inthe following description in terms of the embodiment thereof which isshown in the accompanying drawing. It lS,'tO'b understood, however, thatthe drawing is for the purpose of illustration only, and is not designedas a definition of the limits of the invention, reference being had tothe appended claims for this purpose.

The drawing is a diagrammatic View illustrating an electrical circuitembodying one form of the invention.

In the form of the invention shown in the drawing, there is provided adirect current generator or exciter of conventional type, and indicatedgenerally by the numeral I.

- The exciter I has an armature winding, not shown, but which may be ofconventional type. Connections from the armature winding lead to acommutator 2 having brushes 3 and output lines 5 and 6, to which thereis applied in normal operation a negative and positive potential,respectively.

The exciter I has a field winding 8 connected at one end to the outputline 5 by an electrical conductor 9. The opposite end of the exciterfield winding 8 is connected by a suitable electrical conductor II] tothe regulating switch arm ll of a Tirrill type regulator. The regulatingarm *II is arranged so as to cooperate with suitable switch contacts l2and I3. The contact 12 is connected by an electrical conductor 14 to thepositively charged output line 6 of the exciter l. A resistor 15 isconnected between the lines l0 and M, while a spring 16 biases theswitch arm H in a direction for closing contact [2 to shunt the resistorI5.

The output of the exciter I is controlled'by regulating the excitationof the field winding 8 through the action of the Tirrill type regulatingarm H, as will be explained hereinafter.

The output of the direct current generator or exciter l is connected byconductors 5 and B to the exciting field ll of an alternator, indicatedgenerally by the numeral 20, and having output windings 2|. The excitingfield winding'l'l may be mounted on the same drive shaft as the armature2, and may be rotated in relation to the output windings 2| so as toinduce an alternating current in windings 2! having a value dependentupon the excitation of winding 2| by the exciter l. The shaft forrotating the armature 2' and exciting field winding 2| may be driventhrough a suitable constant speed drive from the aircraft engine orother suitable power source.

Main output lines 22, 23 and 24 lead from the output windings 2i to asuitable electrical load, not shown. 1

The Tirrill type regulating switch arm H has an armature member 25,whereby the arm- H is operated'by the electromagnetic forces applied bywindings 26, 21 and 28.

The main or voltage winding 26 is'fed from transformers 29 havingprimary windings connected across the main lines 22, 23 and 24, andsecondary windings having one end thereof connected through lines 30 toone endjof the winding 26. The opposite end of the winding 26 isconnected through conductor 3| to a rectifier 32 and through conductor33 to the opposite end of the secondary windings of the transformers 29.

Thus, the main winding 26 is responsive to the voltage across the lines22, 23 and 24.

The winding 21 is connected across the exciter field 8 through lines 34and 35. The winding 27 during normal operation has a like polarity tothe winding 26, and is responsive to the voltage across the exciterfield 8. Thewinding 8 limits maximum voltage applied to the exciterfield 8.

The third or compounding winding 28 hasopposite polarity to that ofwinding 26 and 21.

The compounding winding 28 is fed from current transformers 36 havingprimary windings connected in the main lines 22, 23 and 24, and

A secondary windings having one end thereof con nected through line 31to one end of the winding 28. The opposite end of the winding 28 isconnected through conductor 38 to rectifier 39 and through conductor 40to the opposite end of the secondary windings of the transformers 36.

It will be seen that the compounding winding 28 is connected so as tohave an opposite polarity to that of windings and 21, and is energizedin proportion to line current from the current transformers 36 in themain lines 22, 23 and 24.

The compounding winding 28 opposes the winding 26, and thus tends toincrease the voltage setting of the regulator H as the current or loadincreases, while the voltage winding 26 exerts an electromagnetic forcetending to open the contact l2 upon the output voltage exceeding apredetermined value so as to decrease the energization of the exciterfield 8, and thereby the excitation of the exciting winding ll of thealternator 2i and accordingly, the voltage output at lines 22, 23 and24.

In the latter arrangement, in the event of a short across the outputlines 22, 23 or 24, when the short is cleared, the field of the excitermay be reversed. This may be efiected by a kick back from the alternatorresulting upon the collapsing of the magnetic field of the outputwinding 2! effected by the short, and in turn inducing a voltage in theexciting field winding ll, which may be of reverse polarity so as tocause a reversal of the polarity of the exciter field. Thus uponcontinued operation, the exciter may tend to operate with oppositepolarity to that shown.

Under such conditions, the polarity of the winding 21 will be reversedso as to assist rather than oppose the winding 28, and causing in turnthe regulating switch arm II to be biased in a direction opening thecontact [2.

Thus, the regulator would tend to operate in the wrong direction.

The feature of the present invention is the provision of novel means torestore the exciter field 8 to its proper polarity, and to assure properoperation of the regulator. This is specifically effected by providingthe third contact 13, which is connected through a conductor M to thepositively charged conductor 3|, while the conductor 35 is connected byconductor 42 to the negatively charged conductor 30. Thus upon theswitch arm ll being biased downwardly a sufiicient extent due to thereversal of polarity of the exciter field 8, the contact [3 will beclosed, whereupon the exciter winding 8 will be restored to properpolarity, and the regulator will operate in the normal proper manneronce again.

Although only one embodiment of the invention has been illustrated anddescribed, various changes in the form and relative arrangements of theparts, which will now appear to those skilled in the art, may be madewithout departing from the scope of the invention. Reference is,therefore, to be had to the appended claims for a definition of thelimits of the invention.

What is claimed is:

1. In a line voltage regulating system for agenerator including anexciting field winding, an exciter connected across the exciting fieldwinding, a field winding for said exciter, a resistance connected incircuit with said exciter and exciter field winding, a movable switcharm and contact cooperating for shunting the resistance; the improvementcomprising a plurality of electromagnetic windings for biasing saidswitch arm in a direction for opening said contact, one of saidelectromagnetic windings responsive to the voltage output of saidgenerator, another of said electromagnetic windings responsive tothevoltage across the exciter field winding, and a third electromagneticwinding responsive to the current output from said generator, said firstand second mentioned electromagnetic windings normally having a likepolarity and the third electromagnetic winding having a polaritynormally acting in opposition to the polarity of said first and secondmentioned electromagnetic windings, another contact cooperating withsaid switch arm, said second electromagnetic winding eifective upon areversal in the polarity of said exciter field winding to cause saidswitch arm to close said other contact, and means connected in circuitwith said exciter field winding upon the closing of said contact forcorrecting the polarity of the field winding of the exciter.

2. For use with a generator having a field winding, the combination,comprising a movable switch arm and a contact in cooperating relationfor controllin the excitation of said field winding, a plurality ofelectromagnetic windings for biasing said switch arm in a direction foropening said contact, one of said electromagnetic windings responsive tothe voltage output of said generator, another of said electromagneticwindings responsive to the voltage across the field winding, and a thirdelectromagnetic winding affecting said switch arm and responsive to thecurrent output from said generator, said first and second mentionedelectromagnetic windings normally having a like polarity and the thirdelectromagnetic winding having a polarity normally acting in oppositionto the polarity of said first and second mentioned electromagneticwindings, another contact cooperating with said switch arm, said secondmentioned electromagnetic winding efiective upon a reversal of thepolarity of said field winding to cause said switch arm to close saidother contact for correcting the polarity of the field winding.

3. For use with a generator having a field winding, the combinationcomprising a movable switch arm and a contact in cooperating relationfor controlling the excitation of said field winding, electromagneticmeans responsive to a predetermined electrical condition of saidgenerator for operating said switch arm so as to maintain said conditionsubstantially constant, said electromagnetic means including a windingresponsive to the polarity of the field winding, another contactcooperative with said switch arm, said electromagnetic winding eifectiveupon a reversal of the polarity of said field winding to cause saidswitch arm to close said other contact for correcting the polarity ofthe field winding.

CARROLL S. TOWNSEND.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date 1,966,232 Ashbaugh et al. July10, 1934 1,985,679 Jenkins Dec. 25, 1934 2,208,416 Friedlander et al.July 16, 1940 2,259,135 Hill Oct. 14, 1941

